Automatic primer for centrifugal pumps



May 27, 1930. R. L. MORGAN 1,760,313

AUTOMATIC PRIMER FORICENTRIFUGAL PUMPS Filed March 12. 1928 N IN V v 1 f" q N :f1-3 1 Patented May 27, 1930 UNITED STATES RALPH L. MORGAN, OF WORCESTER, MASSACHUSETTS AUTOMATIC PRIMER FOR CENTRIFUGAL PUMPS Application filed March 12, 1928. Serial No. 260,929.

The principal objects of this invention are to provide a primer for centrifugal pumps which will always be ready to prime the pump under all circumstances and will start and stop automatically; to provide means whereby a source of minus pressure can be used for exhausting the air from the pumping system and bringing the water into it; to provide means whereby the rise of water in the primer will shut off the connection automatically with the source of minus pressure and whereby when the water reaches a high pressure in the pump and primer it will automatically close one valve to stop further introduction of water and open another to drain the primer.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which Figs. 1, 2 and 3 are the same cross sectional views of a primer constructed in accordance with this invention and showing the positions of he parts under three different conditions; an

Fig. 4 is a sectional View on the line 4.-4-

of Fig. 1.

The primer comprises a casing or chamber 10, having an inlet 11 connected with the volute of a centrifugal pump 9. The chamber also at the top is connectedthrough a passage 12 with a souipe of minus pressure, 8.

Inside the chamber 10 is cylinder 13 into which the inlet 11 opens. This is closedl by a removable plug 14 at the bottom and provided with a piston 15 therein. At the top of this cylinder is an outlet opening 16 which the top of the piston is adapted to close upon rising to its full height.

In the positions shown in Figs. 1 and 2, the piston is shown in its lowermost position resting on the plug 14. It will be seen that the bottom of the piston is shown frusto conical and that the piston is provided with passages 17 down its sides to allow leakage around it so as to supply water from the pump to the chamber 10. The piston l5 is provided with a recess in the top in which is sup orted a table 19. In this table is a recess 20 or a purpose to be described.

Above the cylinder 13 is a float 21 fiXedly carrying a rod 22 which is shown as extending below the float and entering into the recess 2() for guiding the float. To the top of the rod 22 is fixed a valve 23 adapted to close the port or passage 12.

At one' side is a drain opening 25 adapted to be closed normally by a valve 26 having enough Weight to close tightly by gravity. At the top, the valve, or rather its stem. is provided with a rod 27 adapted, when the valve is raised as shown in Fig. 3, to unseat a ball valve 28 above it and vent the primer. For this action the passage 29 in the stem of the valve 26 is provided. This valve 26 is provided with a circumferential groove 30 into which the edge of the table 19 projects, so that the valve will be opened when the table rises.

The centrifugal pump, of course, will not lift water and means is required to bring the Water from the source of supply to the volute, thus filling the volute with Water and the suction .hose which runs from the source of supply to the inlet side of the centrifugal pump. When this is accomplished the pumping action of this type of pump is established, provided the impeller of the pump is in motion. When an internal combustion engine is used to drive the pump we have a source ofv minus pressure in its inlet manifold. A powerful suction is set up within the inlet manifold which may be4 connected to the passage 12. Other means may be used to obtain a source of minus pressure. Therefore, it will be seen that the air is exhausted from the pump through the course of the arrows in Fig. 1.

After the air has been Withdrawn from the suction hose and pump, water will follow the water to pass upwardly through them fast enough and the pressure acts on the bottom of the piston 15 to force it up to closing position, as shown in Fig. 3. This seals the passage 16 and prevents further water passing into the chamber 10.

When the piston rises it takes with it the table 19, which engages the shoulder above the groove 30 and opens the valve 26 to let the water out of the chamber. At the same time the rod 27 engages the valve 28 and opens it to vent the chamber. In this way the chamber empties quickly. The lioat descends with the water level thus opening the passage to the source of negative pressure.

If thesuction is lost in the pump, the piston l5 will drop back to the position shown in Fig. l and all the other parts will assume the position shown in that figure. Then the process of re-establishing suction in the pump will start at once. After the source of minus pressure is established, the. action of this primer is automatic and it is always ready to perform its function whenever that is required. It constitutesla simple and inexpensive construction. The valve 28 also can act as a safety valve to prevent an excessive pressure building up .in the chamber 10. Although I have mentioned water and intend to use the invention in connection with a water pump, it is to be understood that the invention is adapted to apply to the pumping of liquids in general.

Although I have illustrated and described only one form of the invention I am aware of the fact that modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Y

Therefore, I do not wish to be limited in 'I these respects, but what I do claim is 1. The combination with a centrifugal pump and a source' of minus pressure, of a prlmer for the pump comprising a'casing `having an inlet connected with the normal pressure side of the pump, a cylinder in the casing for receiving liquid directly from the pump', a passage delivering from the cylinder into the chamber of the primer, means whereby when the pressurev in the inlet is low the liquid will flow into the casing through the cylinder, but whenthe pressure is high, communication to the casing will be cut off, the casing being connected with the source of minus pressure, and a iioat valve in the casing for closing the connection between the casing and said source i of minus pressure.

2. The combination with a centrifu al pump and a source of minus pressure, 0% a primer for the pump comprising a casing having an inlet connected with the pressure side of the pump, a cylinder having a piston therein connected for receiving liquid from the pump, said cylinder having a passage delivering into the chamber of the primer .and the piston having passages for allowing liquid to pass by it in a restricted amount, whereby when the pressure on the bottom of the cylinder is great enough so that there is restriction on the passage of liquid around the piston, the piston will rise and close the passage to the chamber, the chamber being connected with a source of minus pressure and means in said chamber for disconnecting it from the source of minus pressure when said piston rises.

3. In a primer for a centrifugal pump, the combination of a casing, a separate cylinder projecting therein, said cylinder being connected with the pressure side of the pump, a piston in the cylinder, means whereby air or liquid can pass by the piston, the cylinder having an opening for discharging it directly into said casing, the casing having an outlet adapted to be connected to a source of minus pressure, means in the casing for closing the outlet of the casing when liquid rises therein, and means whereby the opening from the cylinder will be held closed by the piston as long as it is in itsuppermost position.

4. In a primer for a centrifugal pump, the combination pfya casing having a cylinder therein, saidcylinder being connected at the ,bottom with the pressure side of the ump, a piston in the cylinder, means where y air or liquid can pass by the piston in the cylinder and the cylinder having an opening for discharging it into the casing, the casing having an outlet adapted to be connected with a source of minus pressure, a float 'in said casing having a valve adapted to close the outlet of the casing when liquid rises therein, and means whereby the opening intoy t e casing from the cylinder will be held c osed by the piston as long as it is in vits uppermost position.

5. In an automatic primer for a centrifugal pump, the combination withI a chamber having an outlet adapted to be connected with a source of minus pressure, of a cylinder adapted to be connected with the pump to be primed, a piston in the cylinder having passages to admit liquid under low pressure therethrough, the cylinder having an outlet into the chamber for discharging the liquid into said chamber, a table carried by the piston and an outlet valve for ldraining the .water from the primer arranged to be lifted by said table when the piston rises, thereby opening the last named valve. y 6. In a primer for a centrifugal pump, the combinati-on of a main chamber having an outlet adapted to be connected with a source of inus pressure, a drain outlet and an inlet adapted to be connected with the pump, a valve for closing the first named outlet, a valve for closing the drain outlet, said drain outlet valve having a shoulder thereon, a vent opening having a valve, means carried with when the drain outlet valve is opened, means located Within the chamber and adapted to rise therein when high pressure liquid is admitted through the inlet for shutting -oi' the entrance of Water into the chamber itself, and means arranged to operate when the liquid is shut oil to open the drain outlet valve.

7. In a primer for a centrifugal pump, the combination With a main chamber having an outlet adapted to be connected with a source of minus pressure, of a drain outlet and an inlet, a valve for closing the first named outlet, a Valve for closing the drain outlet, means adapted to rise by the action of high pressure liquid admitted through the inlet for shutting oli the entrance of liquid into the chamber itself, and means operated by the irst named means for opening the drain outlet valve.

In testimony whereof I have hereunto aiXed my signature.

RALPH L. MORGAN. 

